The number of molecules contained in 1 mole of H2S is exactly equal to the Avogadro number:
[tex]N_A = 6,022 \cdot 10^{23} mol^{-1}[/tex]
Therefore, 10 moles of H2S will contain a number of molecules equal to 10 times the Avogadro number:
[tex]N=10 mol \cdot N_A = 6.022 \cdot 10^{24} [/tex]
